Mutual Interference Among Female Anagyrus kamali Moursi (Hymenoptera: Encyrtidae) and its Impact on Fecundity, Progeny Production and Sex Ratio

The solitary endoparasitoid Anagyrus kamali Moursi was introduced to the Caribbean to control populations of Hibiscus Mealybug (HMB) Maconellicoccus hirsutus Green. As part of a biological control programme, mass rearing of A. kamali should produce a maximum of good quality female wasps, because only female parasitoids attack the mealybug. In laboratory experiments conducted at 27 +/- 2°C, mutual interference between female parasitoids on the total oviposition, progeny production and sex ratio was assessed at five parasitoid densities: i.e. 1, 2, 5, 10 and 20 female wasps per 50 mealybugs. Oviposition rates of females decreased with increasing female density, without significantly affecting the sex ratio (average across densities of 0.49 +/- 0.322) (male/female). Under mass-rearing conditions, an increase of the female density from 25 to 75 individuals per cage resulted in an increase of the progeny production from 266 +/- 70.1 to 877.5 +/- 393.3 parasitoids. From 75 to 100 females released per cages, the progeny production was not significantly different with 877.5 +/- 393.3 and 965.3 +/- 608.3 parasitoids produced, respectively. Regardless of the female density, progeny sex ratio remained stable at an average of 0.45 +/- 0.095. As a result, the best efficiency of the mass-production system was obtained at a density of 75 females per cage. However, parasitoid production at this density was inferior to singly caged females by about 50%.     

中国花翅跳小蜂属六新种(膜翅目 :跳小蜂科)(英文)

本文报道采自浙江、福建、广东、云南的跳小蜂六新种 ,即瘤毡蚧花翅跳小蜂MicroterysmetaceronemaeXu、露尾花翅跳小蜂MicroterysnuticaudatusXu、后缘花翅跳小蜂MicroteryspostmarginisXu、拟聂特花翅跳小蜂MicroteryspseudonietneriXu、匀色花翅跳小蜂MicroterysunicolorisXu、赵氏花翅跳小蜂MicroteryszhaoiXu。除露尾花翅跳小蜂MicroterysnuticaudatusXu ,sp .n .寄主尚不明确外 ,其余种类均为林木上各种介壳虫的寄生蜂。对新种进行了详细描述 ,并附特征图。标本存放浙江大学植物保护系。     

Detrimental effects of plant compounds on a polyembryonic parasitoid are mediated through its highly polyphagous herbivore host

Plant defensive compounds can have sometimes severe deleterious effects on both herbivores and their natural enemies. Iridoid glycosides (IGs) are defensive compounds that are well established as deterrent to several generalist herbivores and generalist predators. Trichoplusia ni Hübner (Lepidoptera: Noctuidae) is exceptional among generalist herbivores for its ability to tolerate and thrive when feeding upon IG‐producing plant species; however, it is not known whether the compounds themselves have a harmful effect on T. ni and whether the effects in turn affect its oligophagous endoparasitoid Copidosoma floridanum Ashmead (Hymenoptera: Encyrtidae). To examine these effects, a semi‐purified extract of the IG‐containing plant Plantago lanceolata L. (Plantaginaceae), containing the IGs aucubin and catalpol, was added to artificial diets at 0, 1, 5, or 10% diet dry weight. These diets were fed to both C. floridanum‐parasitized and unparasitized T. ni. Diets higher in IGs tended to be more toxic to both parasitized and unparasitized larvae: host larvae that did survive were slightly smaller and took longer to develop on higher IG diets and total clutch size and survival of the parasitoid C. floridanum were greatly reduced as the host's dietary intake of IGs increased. Only small amounts of aucubin were detected inside the T. ni hemocoel, suggesting that the negative effect of these compounds on C. floridanum is due to nutritional quality of the host being reduced rather than direct toxic effects of the compounds.     

Emergence,dispersal, and mate finding via a substrate‐borne sex pheromone in the parasitoid Metaphycus luteolus

Metaphycus luteolus Timberlake (Hymenoptera: Encyrtidae) is a facultatively gregarious parasitoid of soft scale insects. We conducted behavioral experiments to better understand the mating structure of this species. Emergence of male and female offspring is synchronized, beginning at the onset of photoperiod. Both sexes are able to disperse, although dispersal of males from natal patches appears to take longer than dispersal of females. We demonstrated the presence of a female‐produced contact pheromone using open arena bioassays and motion tracking software, testing residues deposited by walking females, and extracts of females. Males responded to the females' ‘chemical footprints’ and to acetone and hexane extracts of females by searching and arrestment on the chemical residues. Responses of males were dose dependent and diminished with time since the stimulus was deposited. Our findings support the hypothesis that non‐local mating among wasps emerging from different hosts may be quite common in these parasitoids. The implications of our results for the mating structure and previously documented sex ratio patterns of these parasitoids are described.     

Intraguild predation and interference by the mealybug predator Cryptolaemus montrouzieri on the parasitoid Leptomastix dactylopii

The compatibility of the encyrtid parasitoid Leptomastix dactylopii with the coccinellid beetle Cryptolaemus montrouzieri against the citrus mealybug, Planococcus citri, is determined by the extent of intraguild predation and interference by the predator. We tested the preference of the adults and fourth-instar larvae of C. montrouzieri for healthy mealybugs and parasitized mealybugs harboring 1-, 4-, 7- and 14-day-old parasitoid larvae. The experiments were conducted in no-choice (only unparasitized mealybugs or parasitized mealybugs of one parasitoid age were offered at one time) and choice (unparasitized and parasitized mealybugs of a specific age were offered simultaneously) tests. Both the adults and larvae of C. montrouzieri fed on unparasitized and parasitized mealybugs but strongly discriminated against the hardened mummies (14 days old). We also investigated the influence of the presence of C. montrouzieri to the foraging effectiveness of L. dactylopii. The level of parasitism by L. dactylopii was reduced from about 13 to 6% when the number of the C. montrouzieri was increased from zero to four. We recommended that the releases of C. montrouzieri should be conducted 14 days after the releases of L. dactylopii to reduce intraguild predation on the parasitized mealybugs and to avoid interference with the foraging parasitoids.     

Evaluation of the synthetic sex pheromone of the obscure mealybug,Pseudococcus viburni,as an attractant to conspecific males,and to females of the parasitoid Acerophagus maculipennis

The obscure mealybug, Pseudococcus viburni (Signoret) (Hemiptera: Pseudococcidae), is a cosmopolitan pest. In New Zealand, recently introduced management tools include the host‐specific parasitoid Acerophagus maculipennis (Mercet) (Hymenoptera: Encyrtidae) established in 2001, and pheromone‐baited monitoring traps available since 2005. Red delta traps baited with rubber septum lures impregnated with 4.0 μg of the mealybug synthetic sex pheromone, placed in apple orchards in Hawke's Bay and Nelson, trapped both male P. viburni and female A. maculipennis. Two generations of both species per year were discernible, but numbers were low in spring and parasitoids were not trapped during winter (June to September). Male P. viburni catches reached a plateau at a pheromone dose of ca. 1.0 μg per lure but numbers of A. maculipennis per trap increased up to 100 μg per lure, the maximum dose tested. A mathematical model showed that the lures had a half‐life of about 7.4 days and were most attractive to P. viburni with a dose of 0.19 μg, and that the trap effectiveness decreased rapidly once the release rate dropped below the optimum. The model also predicted that the initial pheromone dose should be increased from 0.19 to 5.41 μg per lure as the desired period of deployment increased from 0 to 9 weeks. A dose of 4.0 μg had an initial relative effectiveness of about 55%, reached peak effectiveness after about 5 weeks, and fell to 55% relative effectiveness again after about 8.3 weeks. We conclude that an initial pheromone load of 4.0 μg is appropriate for practical monitoring of P. viburni during the New Zealand summer. Future applications of the sex pheromone for managing the pest and parasitoid are discussed.     

寡索跳小蜂属一新种记述(膜翅目,跳小蜂科)

记述了寡索跳小蜂属Arrhenophagus Aurivillius的1新种,即长距寡索跳小蜂Arrhenophagus longicalcaratus sp.nov.。标本采自于云南省,从柑桔属植物上的盾蚧育得。     

陕西竹子上的蚧虫寄生蜂二新种（膜翅目：跳小蜂科）

报道采自陕西竹子的蚧虫寄生蜂2新种,即寄生白尾安粉蚧Antonina crawi的棒节抑虱跳小蜂Acerophagus clavatus sp.n.和寄生竹半球链蚧Bambusapis hemisphaerica的长尾秀德跳小蜂Pseudectroma longicauda sp.n,对新种进行了详细描述,并附特征图。本文也是抑虱跳小蜂属和秀德跳小蜂属在我国分布的首次记录。标本存放浙江大学植物保护系。     

A survey of mealybugs and their natural enemies in horticultural crops in North Island,New Zealand,with implications for biological control

More than 1300 mealybugs and their natural enemies were collected from six crops (apples, pears, nashi, citrus, persimmon and grapes) at 91 sites. Pseudococcus longispinus and P. calceolariae were the commonest species in all crops, except in pipfruit in Hawkes Bay, inhabited almost exclusively by P. affinis. These three species accounted for more than 99% of all mealybugs collected. Mealybugs were attacked by 14 species of natural enemy, only two of which had been deliberately introduced to New Zealand. Six species of Encyrtidae were reared. Anagyrus fusciventris was recorded from New Zealand for the first time. Parectromoides varipes was newly identified as a primary parasitoid of mealybugs, and males of this species and Gyranusoidea advena, previously unknown, were found. Both species, together with Tetracnemoidea sydneyensis, T. peregrina and T. brevicornis, and Coccophagus gurneyi (Aphelinidae) and two species of Ophelosia (Pteromalidae) were widespread throughout the surveyed regions. Common predators included Cryptolaemus montrouzieri (Col: Coccinellidae), Cryptoscenea australiensis (Neuroptera: Coniopterygidae) and Diadiplosis koebelei (Dipt: Cecidomyiidae). Hyperparasitoids were extremely rare. Five species of ants were recorded tending mealybugs, but none is known to be disruptive to mealybug natural enemies. The implications of these data for biological control of mealybug pests in horticultural crops is discussed, and it is concluded that Pseudaphycus maculipennis (Hym: Encyrtidae) should be introduced against P. affinis. No other importations are recommended. The activity of existing species should be encouraged in future integrated pest management (IPM) programmes, by, for example, distributing A. fusciventris around the country, and commercializing the mass rearing and release of C. montrouzieri.